Method for converting carbon dioxide contained in gases into carbon monoxide



V 0. STALHANE ET AL 2,7,5@

METHOD FOR CONVERTING CARBON DIOXIDE CONTAINED IN GASES INTO CARBON MONOXIDE Filed Sept. 22, 1931 Patented July 9, 1935 UNITED STATES METHOD FOR CONVERTING CARBON DIOX- IDE CONTAINED IN GASES INTO CARBON MoNoxIDE Otto Stalhane and Johan Bertil Stalhane, Stockholm, Sweden Application 1 Claim.

The present invention relates to a method for converting carbon dioxide contained in gases, for instance mixtures of carbon dioxide and carbon monoxide, into carbon monoxide through the ac- 5 tion of finely distributed carbon or carbonpowder, the gaseous mixture being introduced into a chamber where such a high temperature is kept up that the carbon dioxide contained in the gas mixture is entirely or partly converted with the carbon into carbon monoxide. According to the present invention the heat necessary for the process is altogether or partly generated within the reaction chamber by means of an electric current which is passed through electrical resist-- tances arranged inside the furnace.

By way of explanation of the invention there is shown on the accompanying drawing by way of example diagrammatically in vertical section a device suitable for carrying the same into effect, in the shape of a furnace shaft.

l is the furnace chamber surrounded by brickwork 2 and at the bottom provided with an inlet 3 for the gas mixture which is to be regenerated, and this is introduced by means of the fan 4 in the drawing surrounded by the arrows. At the top the regenerated gas passes off through the outlet 5. The shaft widens upwardly for the purpose of making the speed of the current of gas so low in the upper part of the shaft that the carbon powder does not to any appreciable degree pass off with the gas through the outlet 5. The carbon powder 6 is fed into the furnace by means of the screw 1 through the pipe or opening 8 in the shaft, where it meets the current of gas from the inlet or pipe 3 and is with this current of gas carried up into the shaft. The inlet opening 8 for the carbon powder can also be placed higher up in the shaft than is shown in the drawing. In the shaft there are arranged a number of electri cal heating elements 9 through which the heat necessary for the reaction can be applied to the gas. These heating elements may consist, by way of example, of carbon, graphite, carborundum, silite, or the like, or mixtures containing such substances, and provided with contact devices (not shown in the drawing) for the supply of current. Below the elements 9 are arranged shelves It! made of fire-proof material, non-oxidating metal or the like. These shelves are intended to serve as a protection against the heat elements,

not only directly, as a support for the same, but also indirectly, by the carbon powder swirling up through the current of gas partly being deposited on the shelves l and there forming layers H which wholly or partly cover the heating elements 9 and thus protect them against the action of the gas. This protection is particularly valu- September 22, 1931, Serial No. 564,350 In Sweden April 27, 1929 able in the event the heating elements 9 consist of, or contain, carbon, graphite, or the like The heat can also be introduced into the system through heating devices located in or outside the brick work. By way of example of such a heating device or arrangement there is shown in the drawing the channel l2 arranged in the brick work 2. Through its inlet opening I3 are admitted either hot gases or a combustible gas mixture which is allowed to combust in the channel, and the products of combustion pass upwards through the channel l2 and out through the gas outlet I l. The generation or development of the heat can be distributed more evenly by arranging several inlet openings l for the'combustion air.

It will probably be clear Without any further ado that the gas inlet 3 can be arranged in some other Way than that shown in the drawing, that the inlet 8 for the carbon powder can be located higher up in the shaft, that two or more feedopenings 8 for carbon powder etc. can be arranged, while retaining the characteristics of the invention.

If the mixture of gas that is tobe regenerated also contains steam-which is often the case the latter is through the action of the high temperature prevailing in the shaft and the carbon powder wholly or partly converted into carbon monoxide and hydrogen, while at the same time the carbon dioxide is converted into carbon monoxide.

In order to obviate loss of gas or prevent air from penetrating into the shaft, as the case may be, the same may appropriately be lined inside with sheet iron or slabs of fire-proof metal.

The requisite heat may either be altogether generated within the reaction chamber by means of an electrical heating device, or, as has been stated above, only partly in the said manner, partly by means of heating devices located either within or without the walls of the reaction chamber.

Having now described our invention we declare that what we claim is:

.A process for converting carbon dioxide present in gaseous mixtures into carbon monoxide, comprising passing said gaseous mixture together with finely divided carbon through a chamber having heated walls and into contact with a plurality of electrical heating devices having a temperature of at least 1100 C. adapted to supply part of the heat necessary for causing said carbon to react with said gaseous mixture to effect the conversion.

' OTTO STALHANE.

JOHAN BERTIL STALI-IANE 

